Future Contract Benefits - Summary of Changes in Present Values of LFPB (Group Protection) (Details) - Group Protection - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Present Value of Expected LFPB
Balance as of beginning-of-year	$ 5,689	$ 5,462
Beginning balance at original discount rate	6,179	6,059
Effect of changes in cash flow assumptions		(2)	$ (27)
Effect of actual variances from expected experience		(345)	$ (261)
Adjusted balance as of beginning-of-year	5,832	5,771
Issuances	1,641	1,702
Interest accrual	181	159
Benefit payments	(1,476)	(1,453)
Ending balance at original discount rate	6,178	6,179
Effect of cumulative changes in discount rate assumptions	(550)	(490)
Balance as of end-of-period	5,628	5,689
Less: reinsurance recoverables	118	123
Net balance as of end-of-period, net of reinsurance	$ 5,510	$ 5,566
Weighted-average duration of future policyholder benefit liability	5 years	5 years
Cumulative Effect, Period of Adoption, Adjustment
Present Value of Expected LFPB
Balance as of beginning-of-year	$ (490)	$ (597)
Balance as of end-of-period		$ (490)